This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In search of the mechanisms that govern pluripotency and embryonic stem cell (ESC) self-renewal, a growing list of evidence highlights chromatin as a leading factor, controlling ESC maintenance and differentiation. Nuclear envelope (or nuclear lamina) has been proved to play an important role in maintaining chromosomal organization and function. Therefore, we hypothesize that the unique nuclear envelope of ESC could participate in regulation of ESC maintenance and differentiation. Our aim is to identify and compare lamina binding partners from human somatic cells and ESC extracts by a series of pull-down assays, and subsequent analysis by multidimensional protein identification technology (MudPIT) followed by stringent data filtering. This study would reveal a novel role of nuclear lamina in stem cell biology.